The present invention relates to a shield connection structure for a cable, and in particular to a shield connection structure for connecting a shield member of a cable for shielding electromagnetic noise to a metallic cabinet.
In typical conventional shield connection structures, a socket is connected to an end of a shield member of a cable in such a way that the cable is connectable to a metallic cabinet or the like via the socket (disclosed, for example, in Japanese Patent Laid-open Publication No. Hei 11-25749). In such a shield connection structure, the socket is soldered to the end of the shield member. Because this shield connection structure prevents the cable from detaching from the metallic cabinet even when the cable swings due to vibration of the vehicle, this structure is regarded as good shielding of electromagnetic noise.
In this shield connection structure using a socket, however, requirement of soldering makes fixing of the socket to an end of the shield member more difficult or troublesome, and the complexity of the socket structure leads to increased cost. Moreover, in this structure, because contact resistance between the shield member and the metallic cabinet is not considered, sometimes, shielding of electromagnetic noise is insufficient, or sometimes, shielding effect deteriorates over long-term use.
One object of a shield connection structure of the present invention is to achieve more reliable shielding of electromagnetic noise. Another object of the shield connection structure of the present invention is to achieve a simple structure. Still another object of the shield connection structure of the present invention is to achieve sufficient shielding of electromagnetic noise even over a long-term use.
In order to achieve at least one of the above mentioned objects, the cable shield connection structure of the present invention employs the following means.
A cable shield connection structure according to the present invention is a shield connection structure for connecting a shield member of a cable for shielding electromagnetic noise to a metallic cabinet, and comprises a terminal made from material of small electric conductive resistance and connectable to the shield member; and a fixing member for fixing the terminal to the metallic cabinet. In this structure, connection is made such that electric resistance between the shield member and the metallic cabinet is less than a predetermined value.
In this cable shield connection structure of the present invention, connection is made using a terminal which is made from a material having small electric conductive resistance and connectable to a shield member, and a fixing member for connecting the terminal to the metallic cabinet such that electric conductive resistance between the shield member and the metallic cabinet is less than a predetermined value. This arrangement can sufficiently shield electromagnetic noise using a simple structure. Here, xe2x80x9ca predetermined valuexe2x80x9d may be 10 mxcexa9, preferably 1 mxcexa9. These values are based on the fact that electromagnetic noise shielding effect starts to arise approx. 10 mxcexa9, although this may depend on frequencies, and is more effective for 1 mxcexa9 or less. Therefore, when electric resistance between the shield member and the metallic cabinet is set at 10 mxcexa9 or less, electromagnetic noise shielding effect can be achieved. Moreover, when electric resistance between the shield member and the metallic cabinet is set at 1 mxcexa9 or less, improved electromagnetic noise shielding effect can be achieved.
In this cable shield connection structure according to the present invention, the terminal preferably comprises a cylindrical part for being connected to the shield member and a flange for being fixed to the metallic cabinet. In this cable shield connection structure according to the present invention, connection between the cylindrical part of the terminal and the shield member is preferably effected by a caulking connection in which the shielding member is sandwiched between a caulking member and the cylindrical part. This arrangement can connect the shield member and the terminal and easily reduce contact resistance.
In the cable shield connection structure according to the present invention, the terminal is preferably subjected to a corrosion-proofing processing. This enables sufficient shielding of electromagnetic noise, even over long-term use.
Further, in the cable shield connection structure according to the present invention, the fixing member is preferably a member for fixing the terminal to the metallic cabinet in a removable manner. This allows easy maintenance of a device employing the metallic cabinet.
Still further, in the cable shield connection structure according to the present invention, the metallic cabinet is preferably a cabinet of a device to be mounted to a vehicle, including a motor, a generator, and a battery. In a vehicle, because electronics which are easily affected by electromagnetic noise are mounted in a limited space inside of the vehicle, shielding of electromagnetic noise results in a significant effect. Moreover, the cable shield connection structure according to the present invention has a simple structure yet exerts a sufficient connecting force, and therefore achieves sufficient shielding of electromagnetic noise despite vibration due to movement of a vehicle or operation of a vehicle driving device, and continues sufficient shielding over long term use.